Apparatus for treating the inner wall surface of a generally cylindrical duct



Aug. 25, 1970 P VON ARX 3,525,111

APPARATUS FOR TREATING THE INNER WALL SURFACE OF Y A GENERALLY CYLINDRICAL DUCT Filed June 25, 1968 9 Sheets-Sheet l Aug. 25, 1970 p VON ARX 3,525,111

APPARATUS FOR TREATING THE INNER WALL SURFACE 0F A GENERALLY CYLINDRICAL DUCT Filed June 25, 1968 lQSheets-Sheet 2 F i g. 2 B

PAUL VON AEX INVENTOR.

PAUL "JON AF" INVENTOR.

ATTORNEY Au@ 25, 1970 P. VON ARX APPARATUS FOR TREATING THE INNER WALL SURFACE OF A GENERALLY CYLINDRICAL DUCT Filed June 25, 1968 9 Sheets-Sheet 5 P. VON ARX Aug. 25, 1970 APPARATUS FOR TREATING THE INNER WALL SURFACE OF A GENERALLY CYLINDRICAL DUCT 9 Sheets-Sheet 4 Filed June 25, 1968 INVENTOR.

Aug. 25,- 1970 P, VON ARX 3,525,111 l APPARATUS FOR TREATING THE INNER WALL SURFACE oF A GENERALLY CYLINDRICAL DUCT Filed June 25, 1968 9 Sheets-Sheet 5 Fig. 6

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APPARATUS FOR TREATING THE INNER WALL SURFACE OF A GENERALLY CYLINDRICAL DUCT Filed June 25, 1968 9 Sheets-Sheet `SAUL 'JON ARX INVENTOR.

Y mm1 Ross 3,525,11 l INNER WALL SURFACE 0F DRICAL DUCT Aug. 25, 1970 P. voN ARX AEPARATUS FOR TREATING THE A A GENERALLY CYLIN 9 Sheets-Sheet '7 Filed June 25, 1968 INVENTOR.

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PAUL VGN ARX INVENTOR.

TTORNLY Aug. 25, 1970 P. voN ARX 3,525,111

. APPARATUS FOR TREATING THE INNER WALL SURFACE OF A GENERALLY CYLINDRICAL DUCT Filed June 25, 1968 9 Sheets-Sheet 9 TORNEY United States Patent O APPARATUS FOR TREATING THE INNER WALL UURFCTACE F A GENERALLY CYLINDRICAL Paul von Arx, Gelterkinderstrasse 31,

4450 Sissach, Switzerland Filed June 25, 1968, Ser. No. 739,828

Claims priority, application Switzerland, June 28, 1967, 9,375/67; May 14, 1968, 7,430/68 Int. Cl. B08b 9/ 04 U.S. Cl. 15-104.06 14 Claims ABSTRACT OF THE DISCLOSURE A `wheeled support, designed to make at least threepoint contact with the inner wall of a duct to be scraped or coated, is connected via an axially extending rod with two relatively rotatable lhubs each carrying a radial array of tools which sweep the wall surface as the support advances through the duct. A reversing gear train is interposed between the two hubs whereby rotation of one hub about the shaft axis, under the control of a turbine or some other power plant coupled thereto, causes the arrays to rotate in opposite directions; reversal of the driving motion may be used to withdraw the tools from contact with the duct Iwall.

The present invention relates to an apparatus for treating (e.g. scraping or coating) the inner wall surface of a generally cylindrical duct, such as a sewer or a water main.

In the treatment of such duct surfaces it is known to introduce a rotatable tool carrier into the duct and to advance this carrier along the duct axis at a rate so related to the speed of rotation of the tool carrier that the several tools thereof eiectively scrape, polish, coat or otherwise treat every part of the inner wall surface. Diiiculties arise, however, in the presence of internal discontinuities, such as rivet heads, over which the tools must pass; while a resilient mounting of the tools readily enables them to yield inwardly, their return into contact with the wall surface in the wake of the obstacle is generally somewhat delayed (especially in the case of rapidly rotating carriers) so that an untreated zone or shadow remains in the vicinity of any such rivet head or the like. These untreated zones are, however, objectionable since, in the case of a coating, they facilitate the onset of corrosion and since they may allow the accumulation of contaminants.

It is, therefore, an important object of this invention to provide an apparatus for the treatment of such duct surfaces which avoids the drawback just described.

Another object of this invention is to provide means for securely guiding such a rotatable tool carrier along the duct axis even where the shape of the duct departs from linearity; this is particularly important in the case of abrasive or chip-removing tools (such as milling heads) which might otherwise tend to bite into the duct wall at a branching point or a curve.

According to an important feature of my invention, I provide a common well-engaging support for a pair of tool-carrying hubs which are mounted for coaxial rotation on an elongate member extending axially from the support, these hubs being linked by a reversing transmission which causes them to rotate in opposite directions 'whenever power is supplied to them. One of the hubs may be connected directly to a turbine, electric motor or other appropriate drive means; alternatively, the drive means may act upon both hubs through the intermediary of the reversing transmission, e.g. a differential gearing.

In operation, therefore, the sets of tools on the two 3,525,1ll Patented Aug. 25, 1970 carriers approach an internal obstacle from opposite directions so that the shadow left by one set of tools is promptly etfaced by the other set.

In an advantageous embodiment, applicable particularly to paint spreaders and similar coating devices, the source of motive power for the tool carriers is reversible and each carrier is designed to swing an array of tool-supporting arms radially outwardly when rotating in one sense and to withdraw these arms inwardly when rotating in the opposite sense, thus allowing the apparatus to be retracted through the duct (eg. preparatorily to the application of a second coat) without harmful contact between the tools and the coat already applied.

According to another important feature of my invention, the 'Well-engaging support comprises a pair of relatively axially displaceable bosses which, in the nature of an umbrella frame, are interlinked by arms that swing radially outwardly upon a movement of the two bosses toward each other. The outer end of each arm carries a guide roller which yieldably bears upon the inner duct surface under the urging of a spring or other biasing means tending to reduce the spacing of the two bosses. This arrangement ensures that the elongate member carrying the rotatable hubs remains always well centered within the duct even if the diameter of the latter should change within certain limits; it also maintains proper guidance if, e.g. at the junction point with a lateral branch, one of the guide rollers should momentarily lose contact with the duct wall.

The guiding effect is further improved if the umbrellalike array of guide rollers is duplicated at axially spaced locations. Instead of merely providing two identical supporting units for this purpose, I may mount the second set of rollers on a similar umbrella-frame construction associated with a turbine serving as the source of motive power for the tool carriers, the turbine being driven by a flow of water or other fluid passing through the duct itself. In any case, it is highly desirable that at least one set of guide rollers be disposed downstream of the tool carriers as seen in the direction of advance, thereby relieving the revolving tools of the task of feeling their lway through the duct.

In general, the choice of a suitable prime mover for the driving of a tool carrier will depend upon the environment in which the equipment is to be used. For the scraping of sewers and water mains, for example, the aforedescribed type of turbine 'will frequently be suitable; yet in the performance of painting or lubricating jobs involving the spreading of a viscous iiuid, a driving liquid such as water can obviously not be used and reliance must be placed on electric motors or the like. Internal-combustion engines are evidently out of the question when the apparatus is designed to handle a flammable liquid.

My invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a side-elevational view (parts broken away) of an apparatus according to the invention used for the cleaning-of a high-pressure water main;

FIGS. 2A and 2B are cross-sectional views taken on the lines IIA-IIA and IIB-IIB, respectively, of FIG. l;

FIG. 3 is a cross-sectional view of a reversing transmission forming part of the system of FIG. 1;

FIG. 4 is a view similar to FIG. 3, illustrating a modifcation;

FIGS. 5 and 6i are views similar to FIG. 1, illustrating other embodiments;

FIG. 7 is an overall sectional View of a duct in the process of treatment by a coating applicator of the type shown in FIG. 6;

FIGS. 8A and 8B are cross-sectional views generally similar to FIG. 2A or FIG. 2B, showing a modified tool carrier in two different positions;

FIG. 9 is a view similar to FIG. 4, showing a modification of the transmission thereof in combination with a pair of tool carriers of the type illustrated in FIGS. 8A and 8B.

FIG. 10 is an end view taken on the line X--X of FIG. 9;

FIG. 11 is a side-elevational view, partly in section, of a pair of tank cars to be used in combination with the equipment illustrated in preceding gures; and

FIG. 12 is a diagrammatic view generally similar to FIG. 7 showing a duct in the process of being painted by an assembly incorporating the units of FIGS. 9-11.

Reference will rst be made to the system shown in FIGS. 1, 2A, 2B and 3 which comprises an apparatus for the internal cleaning of water pipe W. The principal elements of the apparatus are, from left to right in FIG. 1, a guiding and support unit 10, a rst tool carrier 20, a reversing transmission 30, a second tool carrier 20 and a driving unit 40. The several units are mounted on a rod 50 extending axially within the duct W.

Unit 10 comprises a pair of axially spaced bosses 101, 106, boss 101 being rigid with tube 50 while boss 106 is axially slidable thereon. Boss 101 has a set of fins 102 extending in dilferent radial directions, e.g. three or four such tins spaced 120 or 90 apart. A corresponding number of arms 104 are articulated at 103 to the respective ns 102 and are further connected via associated links 109 with corresponding tins 107 of boss 106, the links 109 being articulated to the iins 107 at 108 and to the arms 104 at 110. The free outer end of each arm 104 has a guide roller 105 joumaled thereon for contact with the inner wall surface of duct W. This contact is yieldably maintained by a biasing device including a pair of lugs 111, 112 on bosses 101 and 106, respectively, an axially extending spindle 113 threadedly received in lug 111 and a spring housing 114 secured to lug 112. A coil spring 114' in housing 114 tends to draw the boss 106 toward the boss 101, thereby swinging the arms 104 outwardly in the manner of an umbrella frame; rotation of spindle 113 allows the maximum separation of the two bosses to be adjusted in order to accommodate ducts of different average diameters.

Units 20 and 20', illustrated in greater detail in FIGS. 2A and 2B, are mirror-symmetrically identical and comprise each a bobbin-shaped hub 201 or 20,2 with flanges 203, 203' or 204, 204 to which a peripheral array of radial brackets 205 and freely swinging arms 208 are attached. The hubs 201 and 202 are journaled on tube 50 by means of ball bearings 301 (FIG. 3). The brackets 205 are secured to the respective lianges by screws 206 and are traversed by pivot pins 207 on which the arms 208 are fulcrurned. These arms, which have the shape of flattened sleeves, are biased for outward swinging (counterclockwise in FIG. 2A, clockwise in FIG. 2B) by leaf springs 210 which pass around the pins 207 into the arms and have their outer ends soldered or otherwise anchored to the respective mounting brackets 205. The outward swing is limited by an adjustable stop 211 in the form of a screw threaded into a nut on a corresponding mounting bracket, another stop in the form of a pin 211V dening the inner limit of the swing.

Each pair of parallel arms 208 on a common pin 207 carry, at their free ends, a set of rotary tools such as milling or scraping heads 209 which are held between these arms with a certain friction so that their peripheral speed is lower than that of the array as a whole. These tools could also be equipped with bristles or pins, as illustrated at 260 in FIG. 2B. With suitable adjustment of the stop 211, the presence of a 'branch W (FIG. 2A) will cause only a limited excursion of the rotary tool, as indicated at 209', so that normal contact with the inner surface of the main duct is soon restored. Arrows X (FIG. 2A) and Y (FIG. 2B) indicate the sense of rotation of each array 20, 20'.

Transmission 30, FIG. 3, is mounted on an enlarged portion S01 of the tubular rod 50 and comprises a differential gear train with two diametrically opposite sun gears 302, 302 which are independently rotatable and mesh with respective planet gears 303:1, 30S-b welded onto the adjoining anges 203, 204 of hubs 201 and 202. Overlapping extensions 304, 305 of these hubs engage each other through ball bearings 306 and form a housing around the sun and planet gears.

The driving unit 40 shown in FIG. 1, and partly illustrated in FIG. 3, comprises a turbine wheel 403 which is freely rotatable on rod 50 but is rigid with the adjoining flange 204 of hub 202. Wheel 403 with its blades 403' is surrounded with small clearance by a ange 405' of a wheel 405 rigid with rod 50, the wheel 405 carrying a set of stationary guide vanes 402 which are fastened at their trailing ends to a sleeve 404 threadedly or otherwise engaging the rod 50 in a relatively fixed position. A spider 411 is axially slidable on sleeve 404 and has radial ribs 410 linked at 409 to a set of arms 408 which at 407 form junctions with a set of deecting plates 401, the latter being pivoted at 406 to the flanged Wheel 405. The pivot pins 407' carry rollers 407 which, like the guide rollers of unit 10, bear upon the inner wall surface of duct W.

When a -body of water rushes through the duct W in the direction of arrow V, it is deflected by plates 401 toward the blades 403' of turbine rotor 403 to turn this rotor and the hub 202 of tool carrier 20 about the axis of the duct in the direction Y (FIG. 2B); tool carrier 20 then rotates in the opposite direction X (FIG. 2A). The water pressure also urges the wheels 407 outwardly against the duct wall and at the same time propels the entire assembly in the direction of arrow V, i.e. to the left in FIGS. 1 and 3. This propulsion may be controlled by a restraining force exerted upon a cable 503 which is hooked onto an eye 502 at the trailing end of rod 50. Furthermore, the water sweeps away fragments of lime, rust and other matter scraped off the inner duct surface.

Whereas in FIG. 1 the assembly is guided at its front by the wheels 105 of unit 10 and at its rear by the wheels 407 of turbine 40. I have illustrated in FIG. 5 an arrangement in which this turbine has been replaced by another guide unit 10 identical with unit 10. This arrangement is particularly applicable where the available Water pressure would be insufficient to operate the Iumbrellatype drive unit 40 of the preceding embodiment. In FIG. 5, motive power is supplied by a modied water turbine 60 having a shell 601 with peripheral apertures 603 secured to flange 204 of carrier hub 202; apertures 603 form a set of rotor vanes co-operating with similar vanes (not shown) in a tubular stator 602 which is unitary with tube 50 and receives a steady stream of water or other uid under pressure via a hose 504 clamped at 505 onto the open trailing end of the tube 50. In this case, separate propulsion means must be provided to advance the assembly through the duct; for this purpose FIG. 5 shows a cable 506 tied to an eye 502 at the leading end of the rod and connected at its opposite extremity to a winch or the like, not shown.

In FIG. 6, which represents an apparatus for the application of a protective coating, the two guide units 10, 10' have been shown interposed between the tool carriers 20, 20 and an electric drive motor 70 therefor, this motor being equipped with reduction gearing not further illustrated. In this instance, both guiding units 10, 10 lie ahead of the applicators 20 and 20', i.e. downstream in the direction of advance V, in order not to disturb the coating of fresh paint deposited on the inner wall surface of the duct. The rotary tools, 261 of these carriers may be brushes or rollers adapted to spread the paint evenly onto the surface; the delivery of the paint to these applicators will be decribed hereinafter with reference to FIG. 7.

Motor 70 is energized via an electric cable 512 entering the duct, together with a towing cable 511, from the downstream side. The hollow rod 50 terminates at the motor housing, the cable 511 being anchored to a stub 50 at the opposite end of this housing. A shaft 510 (FIG. 4), driven by the motor, is journaled within rod 50 with the aid of ball bearings 312 and terminates in the enlarged part 501 thereof where it is keyed to a bevel gear 310 in mesh with another bevel gear`311, the latter being keyed to a transverse pin 313 which is rigid with the sun gear 302 of a modified differential 30" and has the opposite sun gear 302 loosely mounted thereon. Thus, rotation of motor shaft 510 again turns the two tool carriers 20 and 20 in opposite directions as illustrated in FIGS. 2A and 2B.

In FIG. 7 I have shown an assembly A similar to that of FIG. 5, except that the electric motor 70 has |been replaced by an air motor 71 having discharge apertures 72 for air delivered under pressure through a hose 551. This figure also shows three tank cars 80, 81, 82 serving as containers for respective components of the protective coating to be applied; vehicle 80 also acts as a mixing vessel and may include a source of propellant for discharging the mixture F at a controlled rate through a valve-operated outlet 800 onto the floor of the duct ahead of the assembly A. Traction is imparted to the entire train via a cable 550: as the train moves uphill, the flow of the mixture to the applicators is accelerated.

If a reversible power source (such as motor 70 in FIG. 6) is available to drive the tool carriers, a reversal of the input torque may be utilized to withdraw the rotary tools from contact with the inner duct surface, e.g. for the purpose of moving the applicators lback by a certain distance for recoating a previously coated section of the duct. An arrangement enabling such withdrawal has been illustrated in FIGS. 8A, 8B, 9 and l() which show the aforedescribed drive shaft 510 and tubular mounting rod 50 together with a differential gearing 30" generally similar to transmission 30 of FIG. 4.

FIGS. 8A and 8B show one of the two mirror-symmetrical tool carriers 20 associated with transmission 30, these tool carriers comprising a central hub 331 of generally triangular shape which is journaled on a sleeve 336 press-fitted onto the rod 50. Hub 331 is rotatable on that sleeve against the frictional resistance of a pair of brake linings 338 respectively carried on a. flange 336' of sleeve 336 and on a washer 339 pressed against the hub 311 by a pair of Belleville springs 341; the pressure of these springs can be adjusted by a nut 340 engaging the threaded end 336 of the sleve. Cover plates 337 help retain the ball bearings 301 by which the two halves 334, 335 of the differential housing are journaled on rod 50. Each of these two halves has a peripheral array of three lugs 332 to which links 333 are articulated. These links, in turn, are pivotally connected with respective platforms 234 which are also fulcrumed at 330 to corresponding points of the three-cornered hufb 331. The platforms 234 carry Shanks 233 of respective tool holders 232 to which trowel-like tools 231 are fastened. The assembly 330-333 and associated elements have been shown on a larger scale in FIG. 10.

An eye 513 rigid with rod 50 again allows the exertion of traction upon the apparatus to propel it through a duct W.

When the shaft 510 rotates in the direction T (counterclockwise) as indicated in FIG. 8A, the lugs 332 tend to overtake the frictionally retarded fulcral 330 in a manner causing the arms 232 to swing outwardly, thereby applying the trowels 231 to the inner wall surface of duct W. When rotation is reversed, as indicated at U in FIG. 8B, the arms are inwardly retracted to lift the trowels oir" the wall. With an inclined duct, as illustrated at R in FIG. l2, the apparatus may be simply allowed to roll back upon such retraction preparatorily to a recoating; otherwise, special means (e.g. a second cable at the op posite end of the train) would have to be provided for such reversal of motion.

FIG. 11 shows details of a pair of tank cars 85, 86

serving as storage and mixing vessels for the constituents of a multicomponent coat. The vessel has a piston 851 guided on a rod 852 and displaceable to the left under pressure of air admitted through an inlet 853; this piston bears upon a first component K1 which is ejected through a valve-controlled outlet 854 into a hose 855, the conduit system being duplicated on the opposite side of the train. Hose 855 is provided with a clamp 861 serving for a controlled throttling of its throughput. As illustrated in FIG. l2, other tank cars containing components K2, K3, K4 are similarly connected to the same hose 855. A mixing chamber 862 in vessel `886 receives the several components from lboth conduit systems and is equipped with a feed screw `8613, driven by an electric motor `864, for discharging the mixture at a controlled rate onto the floor of the duct. A tube 857 supplies air under pressure to all tank cars in parallel and extends alongside a traction cable 553. A reversible drive motor 90, whose power cable has not been illustrated, turns the rotatable tool carriers 20 on opposite sides of transmission 30 FIG. ll also illustrates a floodlight 865 and a television camera 866 mounted on car 86 to enable remote observation of the coating operation.

Elements shown in different embodiments may be substituted or combined, within the limits of compatibility, or modified in ways apparent to persons skilled in the art without departing from the spirit and scope of my invention as defined in the appended claims.

I claim:

1. An apparatus for treating the inner wall surface of a generally cylindrical duct, comprising:

a support axially displaceable inside a duct to be treated and provided with guide means engageable with the inner periphery of said duct;

an elongate member extending axially from said support;

propulsion means for axially advancing said support and said member through said duct;

. a first hub mounted on said member for rotation about the axis of said duct;

a second hub mounted on said member for rotation about said axis in axially spaced relationship with said first hub;

drive means for rotating said first hub about said axls;

reversing transmission means linking said first hub with said second hub for rotating the latter in a direction opposite the sense of rotation of said first hub, said transmission means including a differential gearing on a part of said member lying between said hubs;

and tool means on each of said hubs engageable with the inner Wall surface of said duct.

2. An apparatus as defined in claim 1 wherein said hubs are provided with overlapping extensions forming a housing around said differential gearing.

3. An apparatus as defined in claim 1 wherein said member is a tube and said differential gearing includes a pin transverse to said axis journaled in said part, a sun gear rigid with said pin, a pair of planet gears in mesh with said sun gear and respectively connected with said hubs, a shaft extending axially within said tube and coupled with said drive means, and gear means in said part drivingly coupling said shaft with said pin.

4. An apparatus as defined in claim 3 wherein said drive means comprises a motor supported on said tube and operatively connected with said shaft.

5. An apparatus as defined in claim 1 wherein said drive means comprises a prime mover on said member, said prime mover being directly coupled with said rst hub.

6. An apparatus as defined in claim 5 wherein said prime mover comprises a turbine.

7. An apparatus as defined in claim 6 wherein said member is a tube, said turbine having an apertured 7 shell forming vanes positioned for irnpingement by a motive fluid transmitted to the interior of said shell through said tube.

8. An apparatus as dened in claim 6 wherein said turbine comprises a rotor on said member rigid with said lirst hub and provided with a peripheral array of blades, a spider axially slidable on said member, a peripheral array of linkages connecting said rotor with said spider, and a set of guide rollers on said linkages engageable with the inner wall surface of said duct, said linkages including a set of deecting plates surrounding said blades and disposed for impingement by a uid stream in said duct to direct the fluid toward said blades while urging said rollers outwardly against said wall surface.

9,. An apparatus as defined in claim 1 wherein said support comprises a tirst boss rigid with said member, a second boss axially slidable on said member, a peripheral array of arms linked with said bosses for outward swinging upon a displacement of said second boss toward said irst boss, and biasing means for urging said bosses toward each other, said guide means including a roller on an outer end of each of said arms.

10. An apparatus as deiined in claim 9, further comprising adjustable stop means for limiting the outward swing of said arms.

11. An apparatus as defined in claim 9 wherein said support is disposed downstream of said hubs.

12. An apparatus as defined in claim 1 wherein said support is duplicated at axially spaced locations along said member, at least one of said locations being downstream of said hubs.

13. An apparatus for treating the inner wall surface of a generally cylindrical duct, comprising:

a support axially dsplaceable inside a duct to be treated and provided with guide means engageable with the inner periphery of said duct;

an elongate member extending axially from said sup- Port;

propulsion means for axially advancing said support and said member through said duct;

a rst hub mounted on said member for rotation about the axis of said duct;

a second hub mounted on said member for rotation about said axis in axially spaced relationship with said first hub;

reversible drive means for rotating said rst hub about said axis;

reversing transmission means linking said first hub with said second hub for rotating the latter in a direction opposite the sense of rotation of said first hub;

tool means on each of said hubs engageable with the inner wall surface of said duct, said tool means including a peripheral array of arms fulcrumed on each of said hubs and swingable in a transverse plane, said transmission means including couplings linking said arms with said drive meas independently of said hubs for rotary entrainment in either direction; `and frictional means for retarding the rotation of said hubs whereby said arms swing outwardly upon rotary entrainrnent in one direction and inwardly upon rotary entrainment in the opposite direction.

14. An apparatus as defined in claim 13 wherein said transmission means comprises a differential gearing having a sun gear coupled with said drive means and having a pair of planet gears in mesh with said sun gear, said couplings including articulated connections between said arms and said planet gears.

References Cited UNITED STATES PATENTS 2,887,118 5/ 1959 Loeiiier et al. 15-104.06 X 3,037,228 6/1962 Cummings 118--3 06 X 3,130,431 4/ 1964 Reinhart 15-104.06

ROBERT W. MICHELL, Primary Examiner U.S. C1. X.R. 

